Many vehicles employ an exhaust gas recirculation (EGR) system to reduce nitrogen oxides (NOx) in an internal combustion engine's exhaust gas and to improve fuel economy. In EGR systems, a portion of the exhaust gas is recirculated to the intake manifold of the engine where the exhaust gas displaces the amount of combustible matter or oxygen normally inducted into the engine, thereby reducing the rate of NOx formation. In addition, many EGR systems implement an EGR cooler in which a coolant is used to cool the exhaust gas. This results in lower combustion chamber temperatures, which in turn increases the effectiveness of the EGR system in reducing the NOx formation.